Recent developments in internal combustion engine technology have led to less harmful emissions and reduced fuel consumption. Exhaust gas recirculation (EGR)—an emissions reduction technique in which a portion of exhaust gasses are fed back into an engine's combustion chamber—is one such technology that has improved internal combustion efficiency. However, due to the high temperatures and pressures of exhaust gasses from combustion engines, those exhaust gasses must often be cooled prior to being introduced back into the combustion chamber.
Heat exchangers known in the prior art typically include components formed from metal castings. A typical casting process involves pouring hot liquid metal into a mold and waiting for the metal to cool and solidify. One advantage of casting over other metalworking processes is that complex shapes can be formed without having to join or fuse multiple components together. Casted components are often able to withstand high temperatures and pressures, in part because they lack the structural weakness of welds or braze joints.
Although casted metal components tend to be robust and able to withstand harsh temperatures and pressures, they are often not suitable for large-scale production or for manufacturing products with varying specifications. A different casting mold is required for each variant of a product. Additionally, metal casting is a more time-consuming manufacturing process compared to other manufacturing processes. The metal must first be melted into a liquid, which is then poured into the mold and left to cool for a period of time before being removed from the casting.
Furthermore, metal casting often involves using disposable or expendable molds that are destroyed during the casting process. For large-scale production, making new molds for each individual component for each different application can be costly and time consuming. Such inflexibility and inefficiency in the casting process might render the manufacture of certain components infeasible.
It is accordingly an objective of the present invention to produce heat exchangers comprising components formed from more efficient and flexible manufacturing processes, such as stamping and/or extrusion to yield heat exchangers, having effective, if not improved heat exchanger capabilities, over those of casted assemblies.
Heat exchangers, such as coaxial coolers used in EGR systems, may vary in size, height, and placement within an engine or exhaust system. Often times, the space within an engine compartment is limited, such that additional components fitted therein must conform to the available space therein. It is therefore another objective of the present invention to provide heat exchangers that are modular and whose components are capable of being readily adapted to different shapes and sizes.
Some vehicles may be subject to stresses and forces that require their engine components to be secured or mounted within its engine bay. Other engine systems may be compact in size and include components mounted to a frame or body to hold them in place. It is therefore another objective of the present invention to provide heat exchangers with mounting hardware.
Coolers typically immerse one or more small-radius gas tubes in liquid coolant. When heated gas flows through the tubes, the tubes themselves are heated. That heat is exchanged with the liquid coolant, which coolant cycles out of a coolant cavity and is then cooled by a separate device before being introduced back into the cavity.
Coolers known in the prior art typically introduce liquid coolant into a coolant cavity through a single port or aperture. As a result, gas tubes in close proximity to that aperture experience greater amounts of cooling compared to gas tubes further away from the aperture.
It is accordingly an objective of the present invention to improve the distribution, consistency, and efficiency of liquid coolant within a coolant cavity.
These and other objectives and advantages will become apparent from the following detailed written description and figures.